Schwannomas of the greater superficial petrosal nerve - case series, discussion of surgical techniques, and review of literature.

BACKGROUND: Facial nerve schwannomas account for about 0.8% of all petrous mass lesions. Schwannomas of the greater superficial petrosal nerve (GSPN) are a rare subtype with few case-reports up to date. CASE PRESENTATIONS: A retrospective analysis of clinical outcomes, radiographic findings and postoperative complication between June 2007 and December 2020 was performed. Four cases of GSPN schwannomas were reported. The presenting symptoms were facial nerve palsy and hearing loss. Imaging studies showed a subtemporal mass on the anterosuperior aspect of the petrous bone, in one case with extraordinary petrous bone and mastoid infiltration and destruction. Three cases were removed through a subtemporal extra- or intradural approach, one case via a combined pre- and retrosigmoid approach. Improvement of facial nerve palsy occurred in one case; new hearing loss was observed in another case. Xeropthalmia was a short-term temporary deficit in three cases. Short- to mid-term follow-up of the patients has not shown any tumor recurrence. CONCLUSIONS: GSPN schwannomas are rare entities presenting with heterogenous symptoms. Our surgical findings emphasize safe resection. Complete remission is possible by GTR. Since the small data set limits the expressiveness of statements regarding standard of care and alternative therapy options, additional data is needed.

Posterior transdural resection of giant calcified thoracic disc herniation in a case series of 12 patients.

Calcified thoracic disc herniations present a rare and challenging entity. Due to the close proximity to the spinal cord and relative narrowing of the spinal canal, the optimal approach remains a matter of debate. While the transthoracic approach is usually preferred, we adapted a new technique described in 2012: the transdural posterior approach. Our aim was to evaluate its benefits in patients with giant thoracic disc protrusions. We retrospectively reviewed all patients treated in our neurosurgical department from July 2012 to March 2020. Demographics, pre- and postoperative clinical status, and operative technique and complications were extracted and analyzed. In total, 12 patients underwent a posterior transdural resection of giant calcified thoracic hard discs between 2012 and 2020. All patients underwent a posterior decompression (laminectomy, hemilaminectomy, or laminoplasty). The median duration of surgery was 152 min. Transient postoperative neurological deterioration occurred in 4 patients, with complete recovery until time of discharge. No patient underwent a surgical revision. The transdural resection of giant calcified thoracic hard discs through a posterior approach provides an excellent decompression with sufficient visualization of the spinal cord and a satisfying postoperative outcome.

The interhemispheric fissure-surgical outcome of interhemispheric approaches.

Exposure of the anterior skull base is challenging due to strategic structures. The interhemispheric approach (IHA) has turned out to be a feasible technique. We report our experience with IHAs in patients with extraaxial lesions (EAL). We performed a retrospective chart review at a tertiary neurosurgical center between April 2009 and March 2020. We included patients with resection of EAL through IHAs concentrating on surgical technique, complete resection rate, postoperative outcome, and complications. Seventy-four patients resected by an IHA were included: 49 (66.2%) frontal (FIA), nine (12.1%) parietooccipital (PIA), and 16 (21.6%) frontobasal IHAs (FBIAs). Median age at time of surgery was 59 years (range 16-88 years), 47 (63.5%) female and 27 (36.5%) male. Complete resection rate was 83.8% (FIA 89.8%, PIA 55.6%, FBIA 81.3%). Rate of new minor deficits was 17.6%, rate of major deficits 5.4%, total rate 23.0%. 51 (68.9%) WHO°I meningiomas, ten (13.5%) WHO°II meningiomas, two (2.7%) WHO°III meningiomas, nine (12.2%) metastases, one (1.4%) sarcoma, and one (1.4%) local adenocarcinoma were resected. Total complication rate was 27.0%. Rate of major complications requiring intervention was 9.6%. Mean follow-up was 34.2 (± 33.2) months. In patients with lesions of the interhemispheric fissure, overall morbidity and complications are comparatively high. Extensions of IHAs with potential even higher morbidity are not necessary though; we support the use of standardized IHAs. Our findings suggest regular usage of relatively feasible IHAs for a satisfying outcome. Invasive, complicated, or contralateral trajectories were not needed.

Intraoperative MRI-based elastic fusion for anatomically accurate tractography of the corticospinal tract: correlation with intraoperative neuromonitoring and clinical status.

OBJECTIVE: Tractography is a useful technique that is standardly applied to visualize subcortical pathways. However, brain shift hampers tractography use during the course of surgery. While intraoperative MRI (ioMRI) has been shown to be beneficial for use in oncology, intraoperative tractography can rarely be performed due to scanner, protocol, or head clamp limitations. Elastic fusion (EF), however, enables adjustment for brain shift of preoperative imaging and even tractography based on intraoperative images. The authors tested the hypothesis that adjustment of tractography by ioMRI-based EF (IBEF) correlates with the results of intraoperative neuromonitoring (IONM) and clinical outcome and is therefore a reliable method. METHODS: In 304 consecutive patients treated between June 2018 and March 2020, 8 patients, who made up the basic study cohort, showed an intraoperative loss of motor evoked potentials (MEPs) during motor-eloquent glioma resection for a subcortical lesion within the corticospinal tract (CST) as shown by ioMRI. The authors preoperatively visualized the CST using tractography. Also, IBEFs of pre- and intraoperative images were obtained and the location of the CST was compared in relation to a subcortical lesion. In 11 patients (8 patients with intraoperative loss of MEPs, one of whom also showed loss of MEPs on IBEF evaluation, plus 3 additional patients with loss of MEPs on IBEF evaluation), the authors examined the location of the CST by direct subcortical stimulation (DSCS). The authors defined the IONM results and the functional outcome data as ground truth for analysis. RESULTS: The maximum mean ± SD correction was 8.8 ± 2.9 (range 3.8-12.0) mm for the whole brain and 5.3 ± 2.4 (range 1.2-8.7) mm for the CST. The CST was located within the lesion before IBEF in 3 cases and after IBEF in all cases (p = 0.0256). All patients with intraoperative loss of MEPs suffered from surgery-related permanent motor deficits. By approximation, the location of the CST after IBEF could be verified by DSCS in 4 cases. CONCLUSIONS: The present study shows that tractography after IBEF accurately correlates with IONM and patient outcomes and thus demonstrates reliability in this initial study.

Changing the clinical course of glioma patients by preoperative motor mapping with navigated transcranial magnetic brain stimulation.

BACKGROUND: Mapping of the motor cortex by navigated transcranial magnetic stimulation (nTMS) can be used for preoperative planning in brain tumor patients. Just recently, it has been proven to actually change outcomes by increasing the rate of gross total resection (GTR) and by reducing the surgery-related rate of paresis significantly in cohorts of patients suffering from different entities of intracranial lesions. Yet, we also need data that shows whether these changes also lead to a changed clinical course, and can also be achieved specifically in high-grade glioma (HGG) patients. METHODS: We prospectively enrolled 70 patients with supratentorial motor eloquently located HGG undergoing preoperative nTMS (2010-2014) and matched these patients with 70 HGG patients who did not undergo preoperative nTMS (2007-2010). RESULTS: On average, the overall size of the craniotomy was significantly smaller for nTMS patients when compared to the non-nTMS group (nTMS: 25.3 ± 9.7 cm(2); non-nTMS: 30.8 ± 13.2 cm(2); p = 0.0058). Furthermore, residual tumor tissue (nTMS: 34.3%; non-nTMS: 54.3%; p = 0.0172) and unexpected tumor residuals (nTMS: 15.7%; non-nTMS: 32.9%; p = 0.0180) were less frequent in nTMS patients. Regarding the further clinical course, median inpatient stay was 12 days for the nTMS and 14 days for the non-nTMS group (nTMS: CI 10.5 - 13.5 days; non-nTMS: CI 11.6 - 16.4 days; p = 0.0446). 60.0% of patients of the nTMS group and 54.3% of patients of the non-nTMS group were eligible for postoperative chemotherapy (OR 1.2630, CI 0.6458 - 2.4710, p = 0.4945), while 67.1% of nTMS patients and 48.6% of non-nTMS patients received radiotherapy (OR 2.1640, CI 1.0910 - 4.2910, p = 0.0261). Moreover, 3, 6, and 9 months survival was significantly better in the nTMS group (p = 0.0298, p = 0.0015, and p = 0.0167). CONCLUSIONS: With the limitations of this study in mind, our data show that HGG patients might benefit from preoperative nTMS mapping.

The impact of preoperative language mapping by repetitive navigated transcranial magnetic stimulation on the clinical course of brain tumor patients.

BACKGROUND: Language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) is used for resection planning in patients suffering from brain lesions within regions known to be involved in language function. Yet we also need data that show whether patients benefit clinically from preoperative rTMS for language mapping. METHODS: We enrolled 25 patients with language eloquently located brain lesions undergoing preoperative rTMS language mapping (GROUP 1, 2011-2013), with the mapping results not being available for the surgeon, and we matched these patients with 25 subjects who also underwent preoperative rTMS (GROUP 2, 2013-2014), but the mapping results were taken into account during tumor resection. Additionally, cortical language maps were generated by analyzing preoperative rTMS and intraoperative direct cortical stimulation (DCS) data. RESULTS: Mean anterior-posterior (ap) craniotomy extents and overall craniotomy sizes were significantly smaller for the patients in GROUP 2 (Ap: p = 0.0117; overall size: p = 0.0373), and postoperative language deficits were found significantly more frequently for the patients in GROUP 1 (p = 0.0153), although the preoperative language status did not differ between groups (p = 0.7576). Additionally, there was a trend towards fewer unexpected tumor residuals, shorter surgery duration, less peri- or postoperative complications, shorter inpatient stay, and higher postoperative Karnofsky performance status scale (KPS) for the patients in GROUP 2. CONCLUSIONS: The present study provides a first hint that the clinical course of patients suffering from brain tumors might be improved by preoperative rTMS language mapping. However, a significant difference between both groups was only found for craniotomy extents and postoperative deficits, but not for other clinical parameters, which only showed a trend toward better results in GROUP 2. Therefore, multicenter trials with higher sample sizes are needed to further investigate the distinct impact of rTMS language mapping on the clinical course of brain tumor patients.

Intraoperative neuromonitoring for function-guided resection differs for supratentorial motor eloquent gliomas and metastases.

BACKGROUND: Recent data show differences in intraoperative neuromonitoring (IOM) in relation to the operated brain lesion. Due to the recently shown infiltrative nature of cerebral metastases, this work investigates the differences of IOM for cerebral metastases and glioma resection concerning sensitivity, specificity, and predictive values when aiming on preservation of motor function. METHODS: Between 2006 and 2011 we resected 171 eloquently located tumors (56 metastases, 115 gliomas) associated with the rolandic cortex or the pyramidal tract using IOM via direct cortical motor evoked potentials (MEPs). Postoperatively, MEP data were re-analyzed with respect to surgery-related paresis, residual tumor, and postoperative MRI with two different thresholds for MEP decline (50 and 80 % below baseline). RESULTS: MEP monitoring was successful in 158 cases (92.4 %). MEPs were stable in 54.7 % of all metastases cases and in 65.2 % of all glioma cases (p < 0.0001). After metastases resection, 21.4 % of patients improved and 21.9 % deteriorated in motor function. Glioma patients improved in only 5.4 % and worsened in 31.3 % of cases (p < 0.05). Resection was stopped due to MEP decline in 8.0 % (metastases) and 34.8 % of cases (gliomas) (p < 0.0002). CONCLUSION: There is significant difference between glioma and metastases resection. Post-hoc, metastases show more stable MEPs but a surprisingly high rate of surgery-related paresis and therefore a higher rate of false negative IOM.

Transcranial Transmission Ultrasound for Reliable Noninvasive Exclusion of Intracranial Hypertension in Traumatic Brain Injury Patients: A Proof of Concept Study.

For many years, noninvasive methods to measure intracranial pressure (ICP) have been unsuccessful. However, such methods are crucial for the assessment of patients with nonpenetrating traumatic brain injuries (TBIs) who are unconscious. In this study, we explored the use of transcranial transmission ultrasound (TTUS) to gather experimental data through brain pulsatility, assessing its effectiveness in detecting high ICP using machine learning analysis. We included patients with severe TBI under invasive ICP monitoring in our intensive care unit. During periods of both normal and elevated ICP, we simultaneously recorded ICP, arterial blood pressure, heart rate, and TTUS measurements. Our classification model was based on data from 9 patients, encompassing 387 instances of elevated ICP (>15 mmHg) and 345 instances of normal ICP (<10 mmHg), and validated through a leave-one-subject-out method. The study, conducted from October 2021 to October 2022, involved 25 patients with an average age of 61.6 ± 17.6 years, producing 279 datasets with an average ICP of 11.3 mmHg (1st quartile 6.1 mmHg; 3rd quartile 14.8 mmHg). The automated TTUS analysis effectively identified ICP values over 15 mmHg with 100% sensitivity and 47% specificity. It achieved a 100% negative predictive value and a 14% positive predictive value. This suggests that TTUS can accurately rule out high ICP above 15 mmHg in TBI patients, indicating patients who may need immediate imaging or intervention. These promising results, if confirmed and expanded in larger studies, could lead to the first reliable, noninvasive screening tool for detecting elevated ICP.

Imaging meningioma biology: Machine learning predicts integrated risk score in WHO grade 2/3 meningioma.

Background: Meningiomas are the most common primary brain tumors. While most are benign (WHO grade 1) and have a favorable prognosis, up to one-fourth are classified as higher-grade, falling into WHO grade 2 or 3 categories. Recently, an integrated risk score (IRS) pertaining to tumor biology was developed and its prognostic relevance was validated in a large, multicenter study. We hypothesized imaging data to be reflective of the IRS. Thus, we assessed the potential of a machine learning classifier for its noninvasive prediction using preoperative magnetic resonance imaging (MRI). Methods: In total, 160 WHO grade 2 and 3 meningioma patients from 2 university centers were included in this study. All patients underwent surgery with histopathological workup including methylation analysis. Preoperative MRI scans were automatically segmented, and radiomic parameters were extracted. Using a random forest classifier, 3 machine learning classifiers (1 multiclass classifier for IRS and 2 binary classifiers for low-risk and high-risk prediction, respectively) were developed in a training set (120 patients) and independently tested in a hold-out test set (40 patients). Results: Multiclass IRS classification had a test set area under the curve (AUC) of 0.7, mostly driven by the difficulties in clearly separating medium-risk from high-risk patients. Consequently, a classifier predicting low-risk IRS versus medium-/high-risk showed a very high test accuracy of 90% (AUC 0.88). In particular, "sphericity" was associated with low-risk IRS classification. Conclusion: The IRS, in particular molecular low-risk, can be predicted from imaging data with high accuracy, making this important prognostic classification accessible by imaging.

The transnasal endoscopic approach for resection of clival tumors: a single-center experience.

Clival tumors present challenging entities regarding their treatment options. Due to their proximity to critical neurovascular structures, the operative goal of gross total tumor resection is rendered more difficult by a high risk of neurological deficits. Retrospective cohort study of patients treated for clival neoplasms through a transnasal endoscopic approach between 2009 and 2020. Assessment of preoperative clinical status, length of operation, number of approaches, pre- and postoperative radiotherapy, and the clinical outcome. Presentation and clinical correlation with our new classification. In total, 59 transnasal endoscopic operations were performed on 42 patients over 12 years. Most lesions were clival chordomas; 63% of the lesions did not reach the brainstem. Cranial nerve impairment was present in 67% of the patients, and 75% of the patients with cranial nerve palsy improved after surgical treatment. Interrater reliability for our proposed tumor extension classification showed a substantial agreement (Cohen's κ = 0.766). The transnasal approach was sufficient to achieve a complete tumor resection in 74% of the patients. Clival tumors exhibit heterogeneous characteristics. Depending on clival tumor extension, the transnasal endoscopic approach can present a safe surgical technique for upper and middle clival tumor resection, with a low risk of perioperative complications and a high rate of postoperative improvement.

Incidence of discoligamentous injuries in patients with acute central cord syndrome and underlying degenerative cervical spinal stenosis.

Introduction: Surgical treatment for CCS in patients with an underlying cervical stenosis without instability remains controversial. Research question: The aim was to assess the incidence of concomitant discoligamentous injury (DLI) in patients with CCS and underlying degenerative cervical spinal stenosis and to determine the sensitivity of MRI by comparing intraoperative site inspection to preoperative imaging findings. Material and methods: We performed a retrospective analysis of our clinical prospective database. Fifty-one patients (39 male, 12 female) between January 2010 and June 2019 were included. Age, sex, neurological deficits, preoperative MRI, and surgical treatment were recorded. Sensitivity was determined by the quotient of patients in whom all levels of DLI were correctly identified on MRI and the total number of patients with intraoperatively confirmed DLI. Results: Mean age at surgery was 64.1 â€‹± â€‹11.3 (range 41-86). DLI was suspected in 33 (62.1%) patients based on MRI findings, which could be confirmed intraoperatively in 29 patients (56.9%). In 2 patients, DLI was detected intraoperatively that was not suspected in preoperative MRI; in 5 patients, another level was affected intraoperatively than was indicated by MRI. The overall specificity and sensitivity of preoperative MRI imaging to identify discoligamentous lesions of the cervical spine was 73% and 79%, respectively. Discussion and conclusion: The incidence of DLI in patients with traumatic CCS based on preexisting spinal stenosis was 60.78%, which is higher than previously reported. The sensitivity of MRI imaging to detect DLI of 79% suggests that these patients are at risk of missing traumatic DLI on imaging.

Postoperative communicating hydrocephalus following glioblastoma resection: Incidence, timing and risk factors.

Introduction: Glioblastoma (GBM) is the most common malignant primary brain tumor. Treatment includes maximally safe surgical resection followed by radiation and/or chemotherapy. However, resection can lead to ventricular opening, potentially increasing the risk for development of communicating hydrocephalus (CH). Complications such as rebleeding and infection may also lead to CH and, eventually, the need for cerebrospinal fluid (CSF) diversion surgery. In this study, we evaluated the incidence of different types of hydrocephalus and potential risk factors for the development of CH following glioblastoma resection. Methods: 726 GBM patients who underwent tumor resection at our department between 2006 and 2019 were analyzed retrospectively. Potential risk factors that were determined for each patient were age, sex, tumor location, the number of resection surgeries, ventricular opening during resection, postoperative CSF leak, ventriculitis, and rebleeding. Uni- as well as multivariate analyses were performed to identify associations with CH and independent risk factors. Results: 55 patients (7.6%) needed CSF diversion surgery (implantation of a ventriculoperitoneal or ventriculoatrial shunt) following resection surgery. 47 patients (6.5%) had CH, on median, 24 days after the last resection (interquartile range: 17-52 days). 3 patients had obstructive hydrocephalus (OH) and 5 patients had other CSF circulation disorders. Ventricular opening (odds ratio (OR): 7.9; p=0.000807), ventriculitis (OR 3.3; p=0.000754), and CSF leak (OR 2.3; p=0.028938) were identified as significant independent risk factors for the development of post-resection CH. Having more than one resection surgery was associated with CH as well (OR 2.1; p=0.0128), and frontal tumors were more likely to develop CH (OR 2.4; p=0.00275), while temporal tumors were less likely (OR 0.41; p=0.0158); However, none of those were independent risk factors. Age, sex, or rebleeding were not associated with postoperative CH. Conclusion: Postoperative CH requiring CSF shunting is not infrequent following GBM resection and is influenced by surgery-related factors. It typically occurs several weeks after resection. If multiple risk factors are present, one should discuss the possibility of postoperative CH with the patient and maybe even consider pre-emptive shunt implantation to avoid interruption of adjuvant tumor therapy. The incidence of CH requiring shunting in GBM patients could rise in the future.

Assessment of the incidence and nature of adverse events and their association with human error in neurosurgery. A prospective observation.

Introduction: Adverse events in surgery are a relevant cause of costs, disability, or death, and their incidence is a key quality indicator that plays an important role in the future of health care. In neurosurgery, little is known about the frequency of adverse events and the contribution of human error. Research question: To determine the incidence, nature and severity of adverse events in neurosurgery, and to investigate the contribution of human error. Material and methods: Prospective observation of all adverse events occurring at an academic neurosurgery referral center focusing on neuro-oncology, cerebrovascular and spinal surgery. All 4176 inpatients treated between September 2019 and September 2020 were included. Adverse events were recorded daily and their nature, severity and a potential contribution of human error were evaluated weekly by all senior neurosurgeons of the department. Results: 25.0% of patients had at least one adverse event. In 25.9% of these cases, the major adverse event was associated with human error, mostly with execution (18.3%) or planning (5.6%) deficiencies. 48.8% of cases with adverse events were severe (≥SAVES-v2 grade 3). Patients with multiple adverse events (8.6%) had more severe adverse events (67.6%). Adverse events were more severe in cranial than in spinal neurosurgery (57.6 vs. 39.4%). Discussion and conclusion: Adverse events occur frequently in neurosurgery. These data can serve as benchmarks when discussing quality-based accreditation and reimbursement in upcoming health care reforms.The high frequency of human performance deficiencies contributing to adverse events shows that there is potential to further eliminate avoidable patient harm.

The Bigger the Better? Analysis of Surgical Complications and Outcome of the Retrosigmoid Approach in 449 Oncological Cases.

Introduction: Exposure of the posterior skull base and the cerebellopontine angle is challenging due to important neurovascular structures. The retrosigmoid approach (RSA) has become the standard method used in surgery. We report our experiences with RSAs regarding technical obstacles, complications, and approach-related outcomes. Materials and Methods: We performed a retrospective chart review at a tertiary neurosurgical center between January 2007 and September 2020. We included all patients undergoing surgery for oncologic lesions through RSAs, concentrating on surgical technique, postoperative outcome, and complications. Results: A total of 449 RSAs were included. The median age at the time of surgery was 58 years; 168 (37.4%) were male and 281 (62.6%) were female. The median approach surface was 7.8 cm2. The median tumor volume was 5.9 cm3. The median Clavien-Dindo grade was 2, the total complication rate was 28.7%, and gross total resection (GTR) was 78.8%. Findings revealed that tumor volume had no significant impact on postoperative complications in general (p = 0.086) but had a significant impact on postoperative hemorrhage (p = 0.037) and hydrocephalus (p = 0.019). Tumor volume was significant for several preoperative symptoms (p < 0.001). The extent of the approach had no significant impact on complications in general (p = 0.120) but was significant regarding postoperative cerebrospinal fluid (CSF) leaks (p = 0.008). Craniotomy size was not significant regarding GTR (p = 0.178); GTR rate just missed significant correlation with tumor volume (p = 0.056). However, in the case of vestibular schwannomas, the size of craniotomy was important for GTR (p = 0.041). Conclusion: Tumor volume has an important impact on preoperative symptoms as well as on postoperative complications. Although the extent of the craniotomy barely missed significance regarding GTR, a correlation can be assumed. Thus, the extent of craniotomy should be taken into presurgical consideration, especially in the case of postoperative CSF leaks. Regarding vestibular schwannomas, craniotomy size plays an important role in achieving satisfactory oncological outcomes. Different approaches should be selected where necessary regarding superior resection rates.

Surgical and Functional Outcome after Resection of 64 Petroclival Meningiomas.

Objective: The management of petroclival meningiomas (PCMs) remains notoriously difficult due to their close association with neurovascular structures and their complex anatomy, hence the surgical paradigm change from radical to functional resection in the past. With this study, we aimed to analyze surgical and functional outcomes of a modern consecutive series of patients with PCMs. Methods: We reviewed patient charts and imaging data of 64 consecutive patients from 2006 to 2018 with a PCM resected at our institution and compared surgical and functional outcomes between subgroups stratified by surgical approach. Results: Females comprised 67.2% of patients (n = 43), with a mean age of 55 years (median 56; range 21-84). Follow-up data were available for 68.8% and reached a mean of 42.3 months (range 1-129) with a median of 28.5 months. The mean tumor diameter was 37.3 mm (standard deviation (SD) 15.4; median 37.0). Infiltration of the cavernous sinus was observed in 34 cases (53.1%), and the lesions affected the brain stem in 28 cases (43.8%). Preoperative cranial nerve palsy was observed in 73.4% of cases; trigeminal neuropathy (42.2%), hearing loss (32.8%), and impairment of vision (18.8%) were the most common. A retrosigmoid approach was employed in 47 cases (78.1%), pterional in 10 (15.6%), combined petrosal in 2 (3.1%), and transnasal and subtemporal in 1 (1.6%). Fifteen cases (23.4%) were resected in a two-staged fashion. Gross total resection (GTR) was attempted in 30 (46.9%) cases without cavernous sinus infiltration and was achieved in 21 (70.0%) of these cases. Surgical complications occurred in 13 cases (20.3%), most commonly meningitis (n = 4; 6.3%). Postoperatively, 56 patients (87.5%) developed new cranial nerve palsy, of which 36 (63.6%) had improved or resolved on last follow up. Achieving GTR was not significantly associated with higher rates of surgical complications (chi-square; p = 0.288) or postoperative cranial nerve palsy (chi-square; p = 0.842). Of all cases, 20 (31.3%) underwent postoperative radiation. Tumor progression was observed in 10 patients (15.9%) after a mean 102 months (median 124). Conclusions: Surgical resection remains the mainstay of treatment for PCMs, with perioperative cranial neuropathies exhibiting favorable recovery rates. Most essentially, the preselection of patients with hallmarks of brain stem affection and cavernous sinus infiltration should dictate whether to strive for a functionally oriented strategy in favor of radical resection.

Surgical Treatment of Intraorbital Lesions.

BACKGROUND: Resection of pure intraorbital tumors is challenging owing to the nearness of the optic apparatus. The objective of this article was to report our experience with different intraorbital tumors and discuss classic approaches and obstacles. METHODS: A retrospective case series of patients who underwent surgery for intraorbital tumors at a tertiary neurosurgical center between June 2007 and January 2020 was performed. RESULTS: The study included 34 patients (median age 58 years; range, 18-87 years; 55.9% [19/34] female, 44.1% [15/34] male). Preoperative proptosis was observed in 67.6% (23/34); visual impairment, in 52.9% (18/34); diplopia, in 41.2% (14/34); and ptosis, in 38.3% (13/34). Intraconal tumors were found in 58.8% (20/34). The most common lesions were cavernous hemangiomas in 26.5% (9/34) and metastases in 14.7% (5/34). Gross total resection rate was 73.5% (25/34). Planned biopsy was performed in 14.7% (5/34). Median follow-up time was 15.5 months (interquartile range: 0-113 months). Surgical approaches included supraorbital approach (23.5% [8/34]), pterional approach (52.9% [18/34]), lateral orbitotomy (14.7% [5/34]), transnasal approach (5.9% [2/34]), and combined transnasal approach/lateral orbitotomy (2.9% [1/34]). Excluding planned biopsies, gross total resection was achieved in 80.0% (12/15) with pterional approach, 100% (7/7) with supraorbital approach, 80.0% (4/5) with lateral orbitotomy, and 100% (1/1) with transnasal approach/lateral orbitotomy. Complication rate requiring surgical intervention was 11.8% (4/34). CONCLUSIONS: Considering the low operative morbidity and satisfactory functional outcome, gross total resection of intraorbital lesions is feasible. We support use of classic transcranial and transorbital approaches. More invasive and complicated approaches were not needed in our series.

Bihemispheric Navigated Transcranial Magnetic Stimulation Mapping for Action Naming Compared to Object Naming in Sentence Context.

Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when another language task is considered, involving verb retrieval in sentence context. Twenty healthy German speakers were tested with object naming and a novel action naming task during nTMS language mapping. Error rates and categories in both hemispheres were compared. Action naming showed a significantly higher error rate than object naming in both hemispheres. Error category comparison revealed that this discrepancy stems from more lexico-semantic errors during action naming, indicating lexico-semantic retrieval of the verb being more affected than noun retrieval. In an area-wise comparison, higher error rates surfaced in multiple right-hemisphere areas, but only trends in the left ventral postcentral gyrus and middle superior temporal gyrus. Hesitation errors contributed significantly to the error count, but did not dull the mapping results. Inclusion of action naming coupled with a detailed error analysis may be favorable for nTMS mapping and ultimately improve accuracy in preoperative planning. Moreover, the results stress the recruitment of both left- and right-hemispheric areas during naming.

Benefit of Action Naming Over Object Naming for Visualization of Subcortical Language Pathways in Navigated Transcranial Magnetic Stimulation-Based Diffusion Tensor Imaging-Fiber Tracking.

Visualization of functionally significant subcortical white matter fibers is needed in neurosurgical procedures in order to avoid damage to the language network during resection. In an effort to achieve this, positive cortical points revealed during preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) can be employed as regions of interest (ROIs) for diffusion tensor imaging (DTI) fiber tracking. However, the effect that the use of different language tasks has on nTMS mapping and subsequent DTI-fiber tracking remains unexplored. The visualization of ventral stream tracts with an assumed lexico-semantic role may especially benefit from ROIs delivered by the lexico-semantically demanding verb task, Action Naming. In a first step, bihemispheric nTMS language mapping was administered in 18 healthy participants using the standard task Object Naming and the novel task Action Naming to trigger verbs in a small sentence context. Cortical areas in which nTMS induced language errors were identified as language-positive cortical sites. In a second step, nTMS-based DTI-fiber tracking was conducted using solely these language-positive points as ROIs. The ability of the two tasks' ROIs to visualize the dorsal tracts Arcuate Fascicle and Superior Longitudinal Fascicle, the ventral tracts Inferior Longitudinal Fascicle, Uncinate Fascicle, and Inferior Fronto-Occipital Fascicle, the speech-articulatory Cortico-Nuclear Tract, and interhemispheric commissural fibers was compared in both hemispheres. In the left hemisphere, ROIs of Action Naming led to a significantly higher fraction of overall visualized tracts, specifically in the ventral stream's Inferior Fronto-Occipital and Inferior Longitudinal Fascicle. No difference was found between tracking with Action Naming vs. Object Naming seeds for dorsal stream tracts, neither for the speech-articulatory tract nor the inter-hemispheric connections. While the two tasks appeared equally demanding for phonological-articulatory processes, ROI seeding through the task Action Naming seemed to better visualize lexico-semantic tracts in the ventral stream. This distinction was not evident in the right hemisphere. However, the distribution of tracts exposed was, overall, mirrored relative to those in the left hemisphere network. In presurgical practice, mapping and tracking of language pathways may profit from these findings and should consider inclusion of the Action Naming task, particularly for lesions in ventral subcortical regions.

Surgical Management of Jugular Foramen Schwannomas.

BACKGROUND: Resection of jugular foramen schwannomas (JFSs) with minimal cranial nerve (CN) injury remains difficult. Reoperations in this vital region are associated with severe CN deficits. METHODS: We performed a retrospective analysis at a tertiary neurosurgical center of patients who underwent surgery for JFSs between June 2007 and May 2020. We included nine patients (median age 60 years, 77.8% female, 22.2% male). Preoperative symptoms included hearing loss (66.6%), headache (44.4%), hoarseness (33.3%), dysphagia (44.4%), hypoglossal nerve palsy (22.2%), facial nerve palsy (33.3%), extinguished gag reflex (22.2%), and cerebellar dysfunction (44.4%). We observed Type A, B, C, and D tumors in 3, 1, 1, and 4 patients, respectively. A total of 77.8% (7/9) underwent a retrosigmoid approach, and 33.3% (3/9) underwent an extreme lateral infrajugular transcondylar (ELITE) approach. Gross total resection (GTR) was achieved in all cases. The rate of shunt-dependent hydrocephalus was 22.2% (2/9). No further complications requiring surgical intervention occurred during follow-up. The median follow-up time was 16.5 months (range 3-84 months). CONCLUSIONS: Considering the satisfying outcome, the GTR of JFSs is feasible in performing well-known skull base approaches. Additional invasive and complicated approaches were not needed. Radiosurgery may be an effective alternative for selected patients.

Surgical Outcome of Trigeminal Schwannomas.

(1) Background: As resection of trigeminal schwannomas is challenging, due to anatomical involvement of the anterior, middle and posterior fossa, the appropriate approach is important. We report our experience with surgical resection of trigeminal schwannomas by simple and classic skull-base approaches. (2) Methods: We performed a retrospective single-center study including patients who underwent surgery for trigeminal schwannoma tumors between June 2007 and May 2020, concentrating on surgical technique, extent of resection, postoperative outcome and complications. (3) Results: We included 13 patients (median age 57.5 with range of 36-83 years, 53.8% (7/13) female. The most common preoperative clinical presentations were facial pain in six (46.2%), hypoacusis in four (30.8%), trigeminal nerve hypesthesia in 11 (V1 46.2% (6/13), V2 (61.5% (8/13), V3 46.2% (6/13)) and headache in three (23.1%) patients. In three cases, the tumor was resected in a two-stage technique. The intradural subtemporal approach was performed in six cases, the extradural technique in two cases, the retrosigmoid approach in five cases, a Kawase approach in two cases and the transnasal endoscopic approach in one case. The gross total resection rate was 76.9% (10/13) and the median follow-up time 24.0 (0-136) months. Three (23.1%) patients developed postoperative anesthesia in at least one branch of the trigeminal nerve. Trigeminal motor function was preserved in 11 (84.6%) patients. Ten of the 11 patients (76.9%) who reported decreased gustation, cerebellar ataxia, visual impairment, or headache improved postoperatively. Two (15.4%) patients exhibited minimal facial palsy (House and Brackmann II-III), which resolved during the follow-up. The total adverse event rate requiring surgical intervention during follow-up was 7.7%. Surgery-related mortality was 0%. (4) Conclusions: Trigeminal schwannomas are rare benign lesions with intra- and extracranial extension. Considering the low operative morbidity and satisfying functional outcome, gross total resection of trigeminal schwannomas is achievable by classic, but also individually tailored approaches. More invasive or combined techniques were not needed with meticulous surgical planning.